James m



(No Model.)

J. M. THOMPSON.

ORE ROASTING FURNACE.

Patented Nov. 22,1881.

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UNITED STATES JAMES M. rnonrson, or SAN rRANCIsCo, CALIFORNIA.

ORE-ROASTING FURNACE.

SPECIFICATION forming part of Letters Patent No. 250,015, dated November 22, 1881,

Application filed March 27, 1880. (No model.)

To all whom it may concern Be it known that I, JAMES M. THOMPSON, of the city and county of San Francisco, and State of California, have invented a new Improvement in Ore-Roasting Furnaces; and I hereby declare that the following is a full and exact description thereof.

My invention relates to open ore-roasting furnaces operating in a continuous manner and in which the ore is exposed to the draft, and my object is to provide a means or arrangement for roasting the finer particles which are carried by the draft simultaneously with the coarser portion and in the same furnace.

My invention, as applied to rotary cylinder furnaces, consists in arranging two inclined revolving cylinders in such a position in respect to each other as to cause the coarser portion of the ore, which will withstand the draft, to be passed through both of them, and at the same time cause the finer particles (which are carried out of the smaller or upper cylinder) to be carried with the draft through thelarger and main roasting-cylinder; and it also consists in a novel construction of the main fire box or boxes at the lower end of the main roastlug-cylinder, by which the ore, after being deposited in the ore-receivin g chamber, is more directly and thoroughly exposed to the reducing action of the heat and flames from the fireboxes than heretofore.

In the accompanying drawings, in which similar letters of reference indicate like parts, Figure]. is a longitudinal elevation in part section. Fig. 2 is an end elevation in part section. Fig. 3 is an end elevation in half-section.

A and B represent two inclined revolving roasting-cylinders, and their positions and approximate sizes in respect to each other are shown in'Fig. 1.

a is the feed-pipe, through which the ore is fed into the upper end of the smaller and upper cylinder, A and b is a chute or pipe,into which the coarser portion of the ore, after it has passed through the cylinder A, is discharged, and through which it is passed into the upper end of the lower cylinder, B.-

G is an upright chamber, into one side of which the lower end of the upper cylinder, A, and the upper end of the lower cylinder, B, project, and having a fine or passage, 0, at or near its bottom, which leadsinto the dust-chambers, (not shown in the drawings;) and D is an upright chamber, into one side of which the opposite ends of the cylinders A and B project, and having an ore-receiving chamber, E, in its lower part or end. This ore-chamber E is divided into two compartments by the partition an.

F F are fire-boxes at opposite sides of the chamber D, the heat and flames from which pass through the downward-inclined passages or flnes d d into each division of the ore-chamber E, and from thence into the cylinder B. By constructing the flues or passages d d with the downward inclination shown the heat and flames from the fire-boxes F F are forced more directly against the surface of the ore in each of the divisions of the ore-chamber E, thus subjecting the ore more thoroughly to the action of the heat and flames.

G is a fire-box at the side of the chamber 0, which communicates with the lower end of the upper cylinder, A; and g is a flue or passage in the side of the chamber O, through which a portion of the draft from the lower cylinder, B, can be passed into the upper cylinder, A, and the amount can be regulated by the valve or damper h; but this flue g and damper h are not absolutely necessary, as sufficient air can be admitted into the cylinder A through the fire-box G or through an opening in the side of the chamber 0.

H is a suction-fan or blower, by which the strength of the current or draft passing upward through the cylinder A can be regulated; and in some cases, when this fan or blower H is used, it will not be necessary to have any fire in the fire-box G, as sutficient draft through the cylinder A can easily be maintained by the blower H to make it equal to that passing upward through the cylinder 13, and by which the fine ore particles would be separated in the upper cylinder from the coarser portion of V the ore and passed through the pipe 6, leading from the blower E into the side of the chamber D. The valve or damper k in the chamber D is also provided to assist in regulating the passage of the draft through the cylinder A; but neither this damper it, nor the blower H and its connecting-pipe i, nor the flue g and valve 70, will be absolutely necessary when a fire is maintained in the fire-box G, as a snfficient draft can then be produced by it through the cylinder A. I

It will be necessary to make the lower cylinder, B, of greater diameter than that of the upper one, as, in addition to the draft or aircnrrent passing out of the upper cylinder into it, the draft and products of combustion from the main fire-boxes F F must also pass through it, and at the same time its area must be so proportioned to that of the upper cylinder that the strength or velocity of the draft through it will not be any greater than that of the draft or current through the upper cylinder, A, so that all the ore which passes down through the cylinder A will also pass through the cylinder B.

The operation of my improved furnace when the upper cylinder, A, is used forpartially roasting or drying the ore, as well as separatingit, is as follows The cylinders A and B are both rotated, while tires are kept burning in the fire-boxes F F and G, the heat and products of combustion from the former passingthrough the lower cylinder, B, and that from the latter passing through both cylinders. The ore is continuously fed through the feed-pipe a into the upper end of the cylinder A, and the coarser portion ofit, which withstands the draft, is progressed through the cylinder and discharged from it in a partially-roasted condition into the chute or pipe I), through which it then passes into the upper end of the cylininder B and is progressed through it and discharged from its lower end into the ore-chant bers E, in which it is exposed to the heat and flames from the fire-boxes F F for a sufiicient time to complete its roasting or chloridization. The residue or finer portion of the ore which does not pass downward through the cylinders is carried by the draft into the chamber D and downward in it until it meets the heat and flames constantly passing into the lower part of the chamber 1) from the fire-boxes F F, and that portion of it which is not carried down and deposited with the coarser portion of the ore is carried by the draft into the lower end of the cylinder B and upward through it into the chamber O, and thence through the flue or passage 0 into dust-precipitating chambers. (Not shown in drawings.) The draft through the cylinder A can be very nicely regulated by the blower H and valves or dampers h and It.

It is evident that the coarser portion of the ore, which passes downward through both cylinders, is exposedin each cylinder to constantly increasing degrees of heat, which is an essential condition for its proper reduction, and the finer portion is roasted and much of it precipitated by the action of the heat and flames from the main fire-boxes F F, while at the same time the chlorine set free (in a chloridizing roasting) by the decomposition of the salt carried back with the finer portion of the ore, and which passes with the draft into the main cylinder B, aids to more thoroughly chloridize the coarser portion of the ore passing downward through that cylinder.

Vhen it is not desired to partially roast or dry the ore before introducing it into the main roasting cylinder or chamber, the fire-box G need not be used, and the requisite draft or aircurrent through the cylinder A is then produced by the blower H.

Having thus described my invention, what I claim is- 1. 1n ore-roasting furnaces, the combination, with the main roasting-furnace, of a preliminary roasting or separating furnace or chamber, having its lower or ore-discharging end connected by chute with the upper or ore-receiving end of the main roasting-furnace, and having its end from which the fine ore is carried by the draft or air-current opening into the main discharge-chamber, and connected thereby with the end of the main roasting-furnace into which the draft and products ofcombustion enter, substantially as and for the purposes described.

2. In an ore-roasting furnace, the combination of the two revolving cylinders A and B with the chambers O and D and fire-boxes F F and Or, and having the lower'end of the upper cylinder connected with the upper end of v the lower one by the chute bin the chamber 0, and their opposite ends opening into the chamber D, substantially as and for the purposes described.

3. In an ore-roasting furnace, the combination, with the chamber D and the chamber 0, having in its side the flue or passage g, of the inclined revolving cylinders A and B, tire-boxes F F and G, feed-pipe a, chute or pipe I), valve or dampers h and k and blower H, and pipe 1', substantially as and for thepurposes described.

4. In an ore-roasting furnace. the combination, with the chamber D and the chamber 0, having in its side the flue or passage g, of the inclined revolving cylinders A and B, fire-boxes F F, feed-pipe a, chute or pipe 11, valves or dampers hand 7c, and blower H,and pipei, substantially as and for the purposes described.

5. The combination, with the ore-roasting chamber of a roastin g-furnace, of the ore-receiving chamber E, divided into two parts by the wall or partition m, and having the fire-boxes F F connected with each of its said parts, substantially as and for the purpose described.

6. In ore-roastin g furnaces, the combination of the two revolving cylinders, the lower connected with the stack by flue, and the upper end of the upper and lower end of the lower cylinder connected by fine, and their other ends connected by chute, and thelower or discharging end of each connected with the fire boxes or chambers in which they rotate,in the manner substantially as and for the purpose described.

JAMES MONROE THOMPSON.

Vitnesses:

E. D. J UDD, F. E. MONTEVERDE. 

